Absorption and Spatial Dispersion in Electromagnetic Susceptibility Models

This thesis focuses on two key aspects of light-matter interactions: absorption and spatial dispersion, both of which are described on a macroscopic scale by the electromag- netic susceptibility. The first part of this thesis contains an investigation into the microscopic origin of absorption in dielectric models, providing a detailed calculation for a long-held assump- tion of the Hopfield model that has formed the basis of many key works on the subject. While previous work has either focused on the quantum regime or used phenomenological methods which lack a clear relationship to the underlying physics, the microscopic model and calculations presented here are purely classical in nature, matching Hopfields initial proposal. A discrete model of a dielectric is developed, containing nonlinear interaction terms between polarizable dipoles and lattice vibrations. The lattice vibrations are found to act as a pseudo-reservoir, leading to broadband absorption of electromagnetic radia- tion that naturally emerges from the model, without the need to add damping terms to the dynamics. The effective linear susceptibility is calculated using a perturbative iteration method and is found to match the form of a model that is widely used for real dielectrics. The second half of the thesis presents a series of modifications to the Halevi-Fuchs susceptibility model, which is used to calculate the electromagnetic reflection and trans- mission coefficients of a spatially-dispersive half-infinite medium. The initial model, valid only for an idealized single-resonance scalar susceptibility with a specific wave vector dependence, is extended to include many more of the susceptibility features found in real materials, including unequal transverse and longitudinal components, multiple res- onances, anisotropy and alternate wave vector dependences. In each case, the effect of the boundary is characterized by a set of phenomenological reflection coefficients for the polarization waves in the medium, with specific values corresponding to various addi- tional boundary conditions for Maxwell’s equations. The exact expressions derived for the electromagnetic reflection and transmission coefficients can be used in the calculation of a range of physical phenomena near the boundary of the medium. This thesis consid- ers the spectral energy density of thermal and zero-point radiation outside the medium, with the key result that the inclusion of spatial dispersion naturally removes an unphysical divergence associated with the use of a spatially local susceptibility model

Studies on the release of endogenous renal dopamine and assessment of the renal dopamine prodrug gludopa in normal man

The diverse experimental approaches into the actions of dopamine in the periphery have demonstrated the amine to possess various interesting features. By activation of distinct receptors it is capable of producing systemic and renal vasodilatation and of modulating sympatho-adrenal outflow. By a combination of haemodynamic and direct tubular effects it is actively natriuretic, and influences hormonal release from the kidney and adrenal cortex.A physiological function in the kidney is strongly suggested by the prod¬ uction and excretion of large amounts of free dopamine, by the close relation¬ ship between dopamine excretion and sodium output in the urine, and by the characterisation of a widespread distribution of dopamine receptors. Such observations do not however, prove that endogenous dopamine has physiological So 3 significance and more compelling evidence accrues when an inhibitor of dopamine can be shown to alter some parameter of normal function. Such studies have been approached using either dopamine receptor antagonists or dopa decarboxylase inhibitors to block dopamine synthesis, and a number of animal models have been utilised, notably in man, dog and rat.It can be concluded for the present studies and from other reported work that dopamine exerts independent action in the kidney, without the requisite mediation of other hormonal, neural or physical factors. More likely is a system of parallel influences, including dopamine, interacting in an array of negative and positive feedback loops, forming a highly complex control mechanism which maintains homeostasis and is able to respond rapidly to changes in the local and wider environment

Solar Gutter and Soffit Facia Systems.

Systems, apparatus, devices and methods of using and mounting solar collectors and photovoltaic collectors in gutters or directly along fascia and eaves and on architectural ledges on buildings, along building walls at various heights above the ground, as well as in ground engaged collectors for providing heated water, power and/or lighting. The collectors can have a pair of conduits/tubes for passing water therethrough. Each of the collectors can be attached to one another by mateably interlocking male and female connectors on the sides of each collector to one another

Critical HRD—Need for Emergence of Critters in Adult Education

Critters seek to expose, understand, and change the underlying causes of a phenomenon—the business of adult education. Adult education is foundational to the engagement of critical management studies (CMS). Critical HRD appears to be a bridge between CMS frameworks and Adult Education theories. Critters will ensure the complexities and breadth of influences get threaded for all stakeholders

The Influence of Servicescape and Local Food Attributes on Pleasure and Revisit Intention in an Upscale-Casual Dining Restaurant

The current study looks at the relationship between servicescape, emotional product involvement, perceived quality of local foods, the positive emotion of pleasure, and revisit intention in an upscale buffet style restaurant on a university campus in the Southeastern U.S. Test results show positive relationships between all of the constructs in the proposed conceptual model. The study also gives practitioners and academics insights into practices that can help to market the use of local foods through the restaurant environment in order to engage emotionally involved customers. This marketing can illicit pleasurable feelings and increase perceived product quality of local foods with the purpose of getting customers to revisit the restaurant. Suggestions for further research on the subject are proposed

The Maturity of Debt Issues and Predictable Variation in Bond Returns

The maturity of new debt issues predicts excess bond returns. When the share of long-term debt issues in total debt issues is high, future excess bond returns are low. This predictive power comes in two parts. First, inflation, the real short-term rate, and the term spread predict excess bond returns. Second, these same variables explain the long-term share, and together account for much of its own ability to predict excess bond returns. The results are consistent with survey evidence that firms use debt market conditions in an effort to determine the lowest-cost maturity at which to borrow

Sound and noisy light: Optical control of phonons in photoswitchable structures

We present a means of controlling phonons via optical tuning. Taking as a model an array of photoresponsive materials (photoswitches) embedded in a matrix, we numerically analyze the vibrational response of an array of bistable harmonic oscillators with stochastic spring constants. Changing the intensity of light incident on the lattice directly controls the composition of the lattice and therefore the speed of sound. Furthermore, modulation of the phonon band structure at high frequencies results in a strong confinement of phonons. The applications of this regime for phonon waveguides, vibrational energy storage, and phononic transistors is examined.National Science Foundation (U.S.). Graduate Research Fellowship (Grant 1122374

Do firms borrow at the lowest-cost maturity? The long-term share in debt issues and predictable variation in bond returns

We document that firms tend to borrow at the lowest-cost maturity. In aggregate time series data, the share of long-term debt issues in total debt issues is negatively related to subsequent excess bond returns, meaning that firms substitute toward long-term debt when the cost of long-term debt is low relative to the cost of short-term debt. The longterm share is also contemporaneously negatively related to the components of the longterm interest rate that predict higher excess bond returns, including inflation, the real short-term rate, and the term spread. The results suggest that firms use predictable variation in excess bond returns in an effort to reduce the cost of capital